Dan Anderson (of http://www.danielandersonphotography.com fame) takes digital photographs of his mounted prints - these digital images are 'matted' and 'framed' using something like Photoshop, and then uploaded to his website.
I tried it, and it works remarkably well. Once you've taken a photograph of the image (preferably using an compressed format such as TIFF), you still have to unsharp mask the image to get back the fuzziness of the digital image, but once you've done that, you're left with a pretty close facsimile of the original photograph.
I'm busy redoing my website, and I plan on re-taking all the website images using this image. It's quick, simple, and looks pretty darn good.